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On Site Guide intelligence

Pirform's intelligence incorporates guidance from the IET's On-Site Guide, specifically Table 7.1(ii). Read more here.

Info

The following applies to flat twin and earth cables. This is wiring type AF in Pirform:

The Pirform wiring type selector showing the flat twin and earth cable type

Ring Final Circuits

The following ring final circuits are recognised as valid by our cable-sizing rules.

Rating Standard Live CPC Reference Methods TN-S
30 mA RCD		 TN-S
No RCD		 TN-C-S
30 mA RCD		 TN-C-S
No RCD
30 3036 2.5 1.5 100,102,A,C 106 41zs 106 106
30 3036 4 1.5 100,102,A,101,103,C 171 48 171 138zs
32 CB or RCBO B/C/D 2.5 1.5 100,102,A,C 106 96zs 106 106
32 CB or RCBO B/C/D 2.5 1.5 100,102,A,C 106 NPzs 106 56zs
32 CB or RCBO B/C/D 2.5 1.5 100,102,A,C 106 NPzs 106 NPzs
32 88-2 (60269-2) 2.5 1.5 100,102,A,C 106vd 32zs 106vd 106vd
32 88-2 (60269-2) 4 1.5 100,101,102,103,A,C 171 38zs 106vd 127zs
32 88-3 2.5 1.5 100,102,A,C 106vd 19ad 106 95zs
32 88-3 4 1.5 100,101,102,103,A,C 171 22zs 171 112zs
32 CB or RCBO B/C/D 4 1.5 100,101,102,103,A,C 171vd 114zs 171vd 171vd
32 CB or RCBO B/C/D 4 1.5 100,101,102,103,A,C 171vd NPzs 171vd 66zs
32 CB or RCBO B/C/D 4 1.5 100,101,102,103,A,C 171vd NPzs 171vd NPzs

Lighting Circuits

The following lighting circuits are recognised as valid by our cable-sizing rules.

Rating Standard Live CPC Reference Methods TN-S
30 mA RCD		 TN-S
No RCD		 TN-C-S
30 mA RCD		 TN-C-S
No RCD
5 3036 1 1 100,101,102,103,A,C 68 68 68 68
5 3036 1.5 1 100,101,102,103,A,C 106 106 106 106
5 88-3 1 1 100,101,102,103,A,C 68 68 68 68
5 88-3 1.5 1 100,101,102,103,A,C 106 106 106 106
6 CB or RCBO B/C/D 1 1 100,101,102,103,A,C 68 68 68 68
6 CB or RCBO B/C/D 1 1 100,101,102,103,A,C 68 65zs 68 68
6 CB or RCBO B/C/D 1 1 100,101,102,103,A,C 68 23zs 68 34zs
6 88-2 (60269-2) 1 1 100,101,102,103,A,C 68 68 68 68
6 CB or RCBO B/C/D 1.5 1 100,101,102,103,A,C 106 106 106 106
6 CB or RCBO B/C/D 1.5 1 100,101,102,103,A,C 106 78zs 106 91zs
6 CB or RCBO B/C/D 1.5 1 100,101,102,103,A,C 106 28zs 106 41zs
6 88-2 (60269-2) 1.5 1 100,101,102,103,A,C 106 106 106 106
10 CB or RCBO B/C/D 1 1 100,101,102,A,C 42vd 42vd 42vd 42vd
10 CB or RCBO B/C/D 1 1 100,101,102,A,C 42vd 32zs 42vd 42vd
10 CB or RCBO B/C/D 1 1 100,101,102,A,C 42vd 23zs 42vd 34zs
10 CB or RCBO B/C/D 1.5 1 100,101,102,A,C 65vd 65vd 65vd 65vd
10 CB or RCBO B/C/D 1.5 1 100,101,102,A,C 65vd 38zs 65vd 51zs
10 CB or RCBO B/C/D 1.5 1 100,101,102,A,C 65vd 28zs 65vd 41zs
10 88-2 (60269-2) 1 1 100,101,102,A,C 42 42 42 42
10 88-2 (60269-2) 1.5 1 100,101,102,A,C 65 65 65 65
16 CB or RCBO B/C/D 1.5 1 100,102,C 34 34 34 34
16 CB or RCBO B/C/D 1.5 1 100,102,C 34 15sc 34 28zs
16 CB or RCBO B/C/D 1.5 1 100,102,C 34 NPad 34 9zs
16 CB or RCBO B/C/D 2.5 1.5 100,101,102,A,C 49 49 49 49
16 CB or RCBO B/C/D 2.5 1.5 100,101,102,A,C 49 24zs 49 44zs
16 CB or RCBO B/C/D 2.5 1.5 100,101,102,A,C 49 NPad 49 14zs
16 88-2 (60269-2) 1.5 1 100,102,C 20 20 20 20
16 88-2 (60269-2) 2.5 1.5 100,101,102,A,C 49 49 49 49
16 88-3 1.5 1 100,102,C 34 34 34 34
16 88-3 2.5 1.5 100,101,102,A,C 34 34 34 34

Radial Final Circuits

The following radial final circuits are recognised as valid by our cable-sizing rules.

Rating Standard Live CPC Reference Methods TN-S
30 mA RCD		 TN-S
No RCD		 TN-C-S
30 mA RCD		 TN-C-S
No RCD
5 3036 1 1 100,101,102,103,A,C 56 56 56 56
5 88-3 1 1 100,101,102,103,A,C 56 56 56 56
5 3036 1.5 1 100,101,102,103,A,C 88 88 88 88
5 88-3 1.5 1 100,101,102,103,A,C 88 88 88 88
6 CB or RCBO B/C/D 1 1 100,101,102,103,A,C 56 56 56 56
6 CB or RCBO B/C/D 1 1 100,101,102,103,A,C 56 56 56 56
6 CB or RCBO B/C/D 1 1 100,101,102,103,A,C 56 23zs 56 33zs
6 88-2 (60269-2) 1 1 100,101,102,103,A,C 56 56 56 56
6 88-2 (60269-2) 1.5 1 100,101,102,103,A,C 88 88 88 88
6 CB or RCBO B/C/D 1.5 1 100,101,102,103,A,C 88 88 88 88
6 CB or RCBO B/C/D 1.5 1 100,101,102,103,A,C 88 78zs 88 88
6 CB or RCBO B/C/D 1.5 1 100,101,102,103,A,C 88 28zs 88 40zs
10 CB or RCBO B/C/D 1 1 100,101,102,A,C 35 35 35 36
10 CB or RCBO B/C/D 1 1 100,101,102,A,C 35 31zs 35 36
10 CB or RCBO B/C/D 1 1 100,101,102,A,C 35 6zs 18ad 17zs
10 CB or RCBO B/C/D 1.5 1 100,101,102,103,A,C 52 52 52 52
10 CB or RCBO B/C/D 1.5 1 100,101,102,103,A,C 52 38zs 52 50zs
10 CB or RCBO B/C/D 1.5 1 100,101,102,103,A,C 10ad 8zs 52 20zs
10 88-2 (60269-2) 1 1 100,101,102,A,C 35 35 35 35
10 88-2 (60269-2) 1.5 1 100,101,102,103,A,C 52 52 52 52
15 3036 1 1 NP NP NP NP
15 3036 1.5 1 NP NP NP NP
15 3036 2.5 1.5 100,102,C 47 47 47 47
15 3036 4 1.5 100,101,102,A,C 76 76 76 76
16 CB or RCBO B/C/D 1 1 C 18 18 18 18
16 CB or RCBO B/C/D 1 1 C 18 13zs 18 13
16 CB or RCBO B/C/D 1 1 C 18 7 8ad NPad
16 88-2 (60269-2) 1.5 1 100,102,C 27 27 27 27
16 88-2 (60269-2) 2.5 1.5 100,101,102,A,C 45 45 45 45
16 88-2 (60269-2) 4 1.5 100,101,102,103,A,C 74 74 74 74
16 88-3 1.5 1 100,102,C 27 27 27 27
16 88-3 2.5 1.5 100,101,102,A,C 45 45 45 45
16 88-3 4 1.5 100,101,102,103,A,C 74 74 74 74
16 CB or RCBO B/C/D 1.5 1 100,102,C 27 27 27 27
16 CB or RCBO B/C/D 1.5 1 100,102,C 27 15zs 27 27
16 CB or RCBO B/C/D 1.5 1 100,102,C 27 NPad 27 9zs
16 CB or RCBO B/C/D 2.5 1.5 100,101,102,A,C 45 45 45 45
16 CB or RCBO B/C/D 2.5 1.5 100,101,102,A,C 45 24zs 45 43zs
16 CB or RCBO B/C/D 2.5 1.5 100,101,102,A,C 45 NPzs 45 14zs
16 CB or RCBO B/C/D 4 1.5 100,101,102,103,A,C 69 32ad 69 69
16 CB or RCBO B/C/D 4 1.5 100,101,102,103,A,C 32ad 16zs 54ad 36zs
16 CB or RCBO B/C/D 4 1.5 100,101,102,103,A,C NPad NPad 18ad 9zs
20 3036 2.5 1.5 100,101,102,A NP NP NP NP
20 CB or RCBO B/C/D 2.5 1.5 100,102,A,C 42 42 42 42
20 CB or RCBO B/C/D 2.5 1.5 100,102,A,C 42 12zs 42 31zs
20 CB or RCBO B/C/D 2.5 1.5 100,102,A,C 42 NPad 42 8zs
20 3036 4 1.5 C 69 43zs 73 66zs
20 CB or RCBO B/C/D 4 1.5 100,101,102,A,C 69 69 69 69
20 CB or RCBO B/C/D 4 1.5 100,101,102,A,C 69 14zs 69 36zs
20 CB or RCBO B/C/D 4 1.5 100,101,102,A,C 69 NPad 69 9zs
20 3036 6 2.5 100,102,A,C 105 69zs 105 105
20 CB or RCBO B/C/D 6 2.5 100,101,102,103,A,C 105 107 105 105
20 CB or RCBO B/C/D 6 2.5 100,101,102,103,A,C 105 23zs 105 58zs
20 CB or RCBO B/C/D 6 2.5 100,101,102,103,A,C 105 NPzs 105 15zs
20 88-2 (60269-2) 2.5 1.5 100,102,A,C 42 42 42 42
20 88-2 (60269-2) 4 1.5 100,101,102,A,C 69 43zs 69 66zs
20 88-2 (60269-2) 6 2.5 100,101,102,103,A,C 105 69zs 105 105
20 88-3 2.5 1.5 100,102,A,C 42 42 42 42
20 88-3 4 1.5 100,101,102,A,C 69 56zs 69 69
20 88-3 6 2.5 100,101,102,103,A,C 105 89zs 105 105
25 CB or RCBO B/C/D 2.5 1.5 C 33 33 33 33
25 CB or RCBO B/C/D 2.5 1.5 C 33 2zs 33 22zs
25 CB or RCBO B/C/D 2.5 1.5 C 33 NPad 33 4zs
25 CB or RCBO B/C/D 4 1.5 100,102,A,C 55 47zs 55 55
25 CB or RCBO B/C/D 4 1.5 100,102,A,C 55 3zs 55 26sc
25 CB or RCBO B/C/D 4 1.5 100,102,A,C 55 NPad 55 4zs
25 CB or RCBO B/C/D 6 2.5 100,101,102,A,C 83 75zs 83 83
25 CB or RCBO B/C/D 6 2.5 100,101,102,A,C 83 5zs 83 43zs
25 CB or RCBO B/C/D 6 2.5 100,101,102,A,C 83 NPzs 83 7zs
25 88-2 (60269-2) 2.5 1.5 C 31 20zs 31 31
25 88-2 (60269-2) 4 1.5 100,102,A,C 53 24zs 53 46zs
25 88-2 (60269-2) 6 2.5 100,101,102,A,C 82 38zs 82 76zs
30 3036 4 1.5 NP NP NP NP
30 3036 6 2.5 C 66 19zs 66 54zs
30 3036 10 4 100,102,A,C 110 31zs 110 89zs
32 CB or RCBO B/C/D 4 1.5 C 43 28zs 43 43
32 CB or RCBO B/C/D 4 1.5 C 43 NPad 43 16zs
32 CB or RCBO B/C/D 4 1.5 C 43 NPad 43 NPad
32 CB or RCBO B/C/D 6 2.5 100,102,A,C 63 45zs 63 63
32 CB or RCBO B/C/D 6 2.5 100,102,A,C 63 NPzs 63 26zs
32 CB or RCBO B/C/D 6 2.5 100,102,A,C 63 NPzs 63 NPzs
32 CB or RCBO B/C/D 10 4 100,101,102,103,A,C 105 74zs 105 105zs
32 CB or RCBO B/C/D 10 4 100,101,102,103,A,C 105 NPad 105 42zs
32 CB or RCBO B/C/D 10 4 100,101,102,103,A,C 105 NPzs 105 NPsc
32 88-2 (60269-2) 4 1.5 C 43 9zs 43 31zs
32 88-2 (60269-2) 6 2.5 100,102,A,C 63 15zs 63 50zs
32 88-2 (60269-2) 10 4 100,101,102,103,A,C 105 24zs 105 82zs
32 88-3 4 1.5 C 43 5zs 43 27zs
32 88-3 6 2.5 100,102,A,C 63 8zs 63 44zs
32 88-3 10 4 100,101,102,103,A,C 105 14zs 105 72zs
40 CB or RCBO B/C/D 6 2.5 C 46 23zs 46 46
40 CB or RCBO B/C/D 6 2.5 C 46 NPzs 46 15zs
40 CB or RCBO B/C/D 6 2.5 C 46 NPzs 46 NPzs
40 CB or RCBO B/C/D 10 4 100,102,A,C 72 37zs 72 72
40 CB or RCBO B/C/D 10 4 100,102,A,C 72 NPzs 72 25zs
40 CB or RCBO B/C/D 10 4 100,102,A,C 72 NPzs 72 NPzs
40 CB or RCBO B/C/D 16 6 100,101,102,103,A,C 118 57zs 118 118
40 CB or RCBO B/C/D 16 6 100,101,102,103,A,C 118 NPzs 118 39zs
40 CB or RCBO B/C/D 16 6 100,101,102,103,A,C 118 NPzs 118 NPad
40 88-2 (60269-2) 6 2.5 C 46 NPzs 46 32zs
40 88-2 (60269-2) 10 4 100,102,A,C 72 NPzs 72 52zs
40 88-2 (60269-2) 16 6 100,101,102,103,A,C 118 NPzs 118 79zs

Glossary

The following abbreviations are used in the tables above:

  • CB: Circuit breaker
  • RCBO: Residual current circuit breaker with overcurrent protection
  • TN-S: Terra neutral - separate
  • TN-C-S: Terra neutral - combined and separate
  • RCD: Residual current device
  • vd: Voltage drop
  • ad: Adiabatic limit
  • zs: Earth fault loop impedance
  • sc: Line to neutral
  • NP: Not permitted
  • NPvd: Not permitted (prohibiting factor: voltage drop)
  • NPad: Not permitted (prohibiting factor: adiabatic limit)
  • NPzs: Not permitted (prohibiting factor: earth fault loop impedance)
  • NPsc: Not permitted (prohibiting factor: line to neutral)